Bulimia nervosa is a significant, perhaps growing, health problem in young women, and is associated with potentially serious medical and psychological problems. Recent controlled studies suggest that both psychotherapeutic and psychopharmacologic treatments for bulimia nervosa are effective. Thus the aim of this study is to examine the comparative and additive efficacy of these two different approaches to treatment. A second aim is to determine whether the more cost-effective group based treatment is as effective as individually administered treatment. Two studies are proposed. In the first, 90 women with bulimia nervosa will be allocated at random to three conditions: Cognitive-behavioral treatment individually administered; pharmacological treatment (desipramine hydrochloride); and the combination of these two treatments. After 16 weeks of treatment, a randomly chosen half of the participants receiving medication will be withdrawn, and those continuing to take medication will be withdrawn at 24 weeks. In the second study, 30 women with bulimia nervosa will, in addition, be allocated at random to group administered cognitive-behavioral treatment, the comparison of interest being between individual and group administered cognitive-behavioral treatments. A multi-level assessment will be carried out before treatment, and at 6, 16, 24, 32, 50, and 68 weeks. Measures will include self- report of binge eating and purging, direct observation of eating behavior, a computer-assisted measure of body image distortion, measures of depression, anxiety, fear of weight gain, self- efficacy, and bulimic thinking, weight change, and serum amylase levels. Selected measures will be repeated more frequently to allow the process of recovery with the different therapies to be documented. The findings from this study may throw light not only on the treatment of bulimia nervosa, but on the treatment of other eating disorders such as anorexia nervosa with bulimia, and binge eating in the obese.